The first WHI study results, published in 2004, reported on the effect that estrogen had on women who had had a hysterectomy. At this point, the researchers were looking at what took place after the women had taken the drug an average of 3.5 years. They found that the women on estrogen had a decrease in fractures and an increase in stroke and blood clots compared with those on the placebo. They also found that estrogen did not reduce or increase a woman’s risk of having a heart attack. In addition, the findings suggested that estrogen might also decrease breast cancer risk.

The current report looked at the same women 10 years after entering the study and five years after they stopped taking estrogen. It showed that most of the benefits and risks associated with estrogen stopped when women discontinued taking it. However, a small decrease in breast cancer risk persisted.

This decease is interesting, but it’s hard to interpret. Did it occur because some of the women had their ovaries removed when they had their hysterectomy, which would also have significantly lowered their breast cancer risk? Unfortunately, the study report doesn’t differentiate between women who had their ovaries removed and women who did not—so there is no way to know the answer.

Even so, this report is still good news. It means that women who have had a hysterectomy can safely take estrogen alone for a short time (about 3.5 years) and they might also experience a potential decrease in breast cancer risk. It does not mean that long-term use is safe and indeed studies have suggested that long-term use still increases breast cancer risk albeit less than that of combined hormones. And it doesn’t address young women who have to have a hysterectomy.

Lives were saved because of research

Some reporters have suggested that studies like the WHI just confuse women. I beg to differ. First of all, the WHI’s Estrogen Plus Progestin Study clearly showed the danger of taking this combination after menopause. The year after the report came out the incidence of breast cancer decreased 8% in the United States and in all of the other countries where combination hormone replacement therapy had been widely used. Lives were saved because of this study!

Secondly, the purpose of research is not to confirm what we think we know but rather to find out whether it is true. We originally assumed that the ovaries stopped functioning at menopause. This was based on the fact that hormone levels were hard to detect in the blood with the techniques available at the time. But that assumption was wrong! The ovaries continue to produce small amounts of estrogen as well as the precursors of estrogen, which are made into the hormone in the organs themselves. When estrogen replacement caused uterine cancer we assumed that the progestin we added would only affect the uterus and not any other organs. But this assumption was also wrong! We now know that the combination is worse for the breast. Without research, we would still have those additional breast cancer cases.

Our understanding of what estrogen does in the breast has been challenged by this research because these findings suggest that short-term estrogen use results in some breast cancer protection. And this is the type of unexpected finding we need, because it forces us to relinquish our assumptions, which is what moves science forward. We fought in the nineties to have more research on women, so let’s not complain when the data doesn’t always come out the way we think they should!

As scientists go back to the drawing board to try and figure out what this research means, we should give thanks to all the women who participated in these studies. If we all take advantage of every opportunity to be part of research, the answers we need will come more quickly. I started the Love/Avon Army of Women (www.armyofwomen.org) to give women an easy way to find out about these studies. Now it is time for you to do you part and join me!